Ingredients

2 tbsp whole buckwheat, soaked in water for 12 hours, then drained and dried out on a tray

6 sheets nori seaweed

80 ml mirin

80 ml sake

60 ml soy sauce

2 tbsp balsamic vinegar

1 green papaya

1 jicama, (yam bean)

1 green mango

1 coconut

handfuls coriander

2 sprigs green peppercorns

4 limes, zest of 1, juice of all

1 lump pale palm sugar

1 tbsp fish sauce

extra virgin olive oil, for garnish

Method

1. Depending on the shape of the tuna, cut it into roughly 3 x 3cm batons. Rub with the sesame oil then sear in a hot pan on all sides for no more than 30 seconds. Immediately wrap tightly in cling film and plunge into a bowl of iced water.

2. Heat 1cm of vegetable oil in a small pan to about 60C . Add the buckwheat and fry over moderate heat till it turns golden and become crunchy. Drain and sprinkle with sea salt.

3. Toast 4 sheets of the nori over an open flame then crumble them up into a bowl. Crumble the un-toasted sheets too.

4. Bring the mirin, sake, soy and balsamic to a simmer then add the nori and cook for 20 seconds, stirring often. Tip into a jug and blitz with a stick blender. Leave to cool.

5. Peel the papaya and jicama and finely julienne ¼ of them. Julienne ¼ of the mango (it doesn't need peeling) and add to the others.

6. Crack open the coconut and finely grate 3 tablespoons of it into the fruit. Pick the leaves from the coriander and cut the stalks into 1cm pieces then add to the fruit as well.

7. To make the dressing, put the peppercorns, lime zest and palm sugar in a mortar and pound them to break up the peppercorns. Mix in the lime juice and fish sauce and adjust seasoning.

8. To serve, dollop some of the seaweed puree on the plate. Mix the dressing with the papaya salad and place on the plate. Slice the tuna and lay on top. Sprinkle lightly with sea salt, scatter some buckwheat over then drizzle with the olive oil.